In living organisms, Ca2+ signalling is central to cell physiology. The Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) has been widely used as a probe to test the role of calcium in a large variety of cell functions. Here we show that in most cell types BAPTA has a potent actin and microtubule depolymerizing activity and that this activity is completely independent of Ca2+ chelation. Thus, the depolymerizing effect of BAPTA is shared by a derivative (D-BAPTA) showing a dramatically reduced calcium chelating activity. Because the extraordinary depolymerizing activity of BAPTA could be due to a general depletion of cell fuel molecules such as ATP, we tested the effects of BAPTA on cellular ATP levels and on mitochondrial function. We find that BAPTA depletes ATP pools and affects mitochondrial respiration in vitro as well as mitochondrial shape and distribution in cells. However, these effects are unrelated to the Ca2+ chelating properties of BAPTA and do not account for the depolymerizing effect of BAPTA on the cell cytoskeleton. We propose that D-BAPTA should be systematically introduced in calcium signalling experiments, as controls for the known and unknown calcium independent effects of BAPTA. Additionally, the concomitant depolymerizing effect of BAPTA on both tubulin and actin assemblies is intriguing and may lead to the identification of a new control mechanism for cytoskeleton assembly.
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http://dx.doi.org/10.1111/j.1432-1033.2004.04259.x | DOI Listing |
Adv Sci (Weinh)
May 2023
Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China.
Pyroptosis, systemic inflammation, and mitochondrial apoptosis are the three primary contributors to sepsis's multiple organ failure, the ultimate cause of high clinical mortality. Currently, the drugs under development only target a single pathogenesis, which is obviously insufficient. In this study, an acid-responsive hollow mesoporous polydopamine (HMPDA) nanocarrier that is highly capable of carrying both the hydrophilic drug NAD and the hydrophobic drug BAPTA-AM, with its outer layer being sealed by the inflammatory targeting peptide PEG-LSA, is developed.
View Article and Find Full Text PDFMol Biol Cell
December 2022
Ottawa Hospital Research Institute, The Ottawa Hospital-General Campus, Ottawa, ON K1H 8L6, Canada.
The extent to which calcium signaling participates in specific events of animal cell meiosis or mitosis is a subject of enduring controversy. We have previously demonstrated that buffering intracellular calcium with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA, a fast calcium chelator), but not ethylenebis(oxyethylenenitrilo)tetraacetic acid (EGTA, a slow calcium chelator), rapidly depolymerizes spindle microtubules in oocytes, suggesting that spindle assembly and/or stability requires calcium nanodomains-calcium transients at extremely restricted spatial-temporal scales. In this study, we have investigated the function of inositol-1,4,5-trisphosphate receptor (IPR), an endoplasmic reticulum (ER) calcium channel, in spindle assembly using Trim21-mediated depletion of IPR.
View Article and Find Full Text PDFJ Integr Plant Biol
June 2022
College of Grassland Agriculture, Northwest A&F University, Yangling, 712100, China.
Microtubules are dynamic cytoskeleton structures playing fundamental roles in plant responses to salt stress. The precise mechanisms by which microtubule organization is regulated under salt stress are largely unknown. Here, we report that Arabidopsis thaliana MICROTUBULE-DESTABILIZING PROTEIN 25 (MDP25; also known as PLASMA MEMBRANE-ASSOCIATED CATION-BINDING PROTEIN 1 (PCaP1)) helps regulate microtubule organization.
View Article and Find Full Text PDFMol Biol Cell
November 2016
Ottawa Hospital Research Institute, Ottawa Hospital-General Campus, Ottawa, ON K1H 8L6, Canada
Intracellular calcium transients are a universal phenomenon at fertilization and are required for egg activation, but the exact role of Ca in second-polar-body emission remains unknown. On the other hand, similar calcium transients have not been demonstrated during oocyte maturation, and yet, manipulating intracellular calcium levels interferes with first-polar-body emission in mice and frogs. To determine the precise role of calcium signaling in polar body formation, we used live-cell imaging coupled with temporally precise intracellular calcium buffering.
View Article and Find Full Text PDFJ Neurosci
January 2013
Department of Physiology, University of Toronto, Toronto, Ontario, Canada.
Low-frequency depression (LFD) of transmitter release occurs at phasic synapses with stimulation at 0.2 Hz in both isolated crayfish (Procambarus clarkii) neuromuscular junction (NMJ) preparations and in intact animals. LFD is regulated by presynaptic activity of the Ca(2+)-dependent phosphatase calcineurin (Silverman-Gavrila and Charlton, 2009).
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